Coffee dispensing machines are well known in the art. They usually include a manually operable valve provided with a handle actuated by a user to fill a cup to an appropriate level. This level is mainly determined by the hand-eye coordination of the user.
While the operation of this type of coffee dispensing machine is satisfactory when relatively low volumes of coffee has to be transferred from a main reservoir to cups, it is not so when the number of cups to be filled in a small period of time is high, for example, in hospital kitchens where hundreds of meals are prepared three times a day.
Indeed, for the workers of these volume feeding kitchen systems, it is generally difficult to manually transfer a predetermined quantity of coffee cup after cup when the number of cups to be filled is great and the time allotted to the cup filling operation is short. Furthermore, the risk of injury to the workers is increased since the worker's hands are necessarily in the vicinity of the manual valve during the transfer operation and may thus be scalded.
Three solutions have been proposed to overcome this drawback of conventional coffee dispensing machines.
The first solution involves the use of a timer-operated valve that, when an actuator is depressed, is opened for a predetermined duration. The drawback with this solution is that the quantity of coffee transferred by the valve from a main reservoir to a cup is a function of the quantity of coffee remaining in the main reservoir since the flow rate of the coffee through the valve is a affected by gravity.
The second solution also involves a timer-operated valve. However, instead of transferring a quantity of already prepared coffee from a main reservoir to a cup, a coffee-making syrup is mixed with hot water upon demand and transferred to the cup. This eliminates the above-mentioned drawback of the first solution since the hot water is contained under pressure, thus allowing the quantity of water transferred to be predetermined. It is however to be noted that the mix of coffee-making syrup and hot water produces a liquid that does not taste exactly like coffee that may cause gastric problems.
The third solution involves the use of a type of coffee machine making the coffee on a cup-by-cup basis upon activation of an actuator. A major drawback of this solution is the relatively long time required to brew a cup of coffee each time the machine is activated, making this type of machines inadequate for volume feeding kitchen system uses. Furthermore, the quantity of coffee beans required to make one cup of coffee with this type of machine is greater than with coffee machines making a reservoir of coffee at a time.